If you do a search on Dhamma Wheel on 'alcoholism' and 'addiction', you should be able to pull up a number of threads that will be of benefit.
Your mother has really got to be the one who is motivated to give up alcohol. If she hasn't got the motivation it won't matter what approach you use. If she does have the motivation, I would be inclined to direct her towards a 12-step program or get a referral to the drug and alcohol clinic at a major hospital close to where you live. I know some people within my own tradition having success with breaking their addictions by attending a ten-day course of vipassana meditation/ Again, the individual needs to have a strong motivation to free themselves from addiction otherwise they won't stay the ten-days or after completing the course they go back to their addiction.
All the very best and I wish your mother a swift recovery